The present invention relates to drill bits and more particularly to drill bit blades for drilling into masonry, rock and like hard brittle material.
Drill bit blades for drilling into rock, concrete, masonry material and similar brittle material are per se known. These drill bit blades are typically fabricated of tungsten carbide.
Typically also, drill bit blades for drilling into masonry, rock, concrete, and like hard brittle material have planar lateral side surfaces, flank end surfaces oriented at an angle to the lateral side surfaces defining flank cutting edges at the intersections of the flank end surfaces and the lateral side surfaces, and tip face surfaces converging from the flank end surfaces to the center of the drill bit blade defining a chisel edge at the intersection of the two tip face surfaces. The tip face surfaces are also oriented at an angle to the lateral side surfaces defining lateral cutting edges at the intersections of the tip face surfaces and the lateral side surfaces. These heretofore known drill bit blades thus have a long chisel edge and present a flat apex in profile or side view.
A problem with such typical drill bit blades is that they have a tendency to "walk" that is they are difficult to hold at the center of a hole to be drilled when beginning to drill a hole because of the long chisel edge and flat or blunt blade profile. In addition, also due to the long chisel edge and blunt profile, a large feed thrust force and large torque force are required to force the drill bit blade into the material to be drilled.